JPH0841511A - Control of blast furnace and device therefor - Google Patents

Abstract

PURPOSE:To provide a control method of a blast furnace, by which the reducing efficiency can be improved and the stability of the operation is obtd., and device therefor by adjusting an ore layer thickness distributing ratio in the charged material according to the condition in the furnace. CONSTITUTION:The center part X of the blast furnace positioned in the interval from the lower part of a shaft to the upper part of a barrel part on the center line of the blast furnace 10 and the tip part Y of a tuyere are connected with a straight line, and the average temp. of furnace gas at plural points in the furnace center side and the furnace wall side from the straight line XY is obtd. A relative ratio of O (iron source wt.)/C (coke wt.) of the charged material from the furnace top part is adjusted in the furnace diameter direction so that the average temp. of the furnace center side keeps a value higher than that of the furnace wall side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention can improve the reduction efficiency by adjusting the relative O (iron source weight) / C (coke weight) in the furnace radial direction according to the situation in the furnace, and can improve the reduction efficiency in the blast furnace situation. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blast furnace control method and apparatus that can achieve stability.

[0002]

2. Description of the Related Art In a blast furnace, iron raw materials and coke are alternately charged and iron oxide is heated and reduced by a high-temperature reducing gas rising in the furnace. The generated iron is melted, dropped into the lower part of the furnace, and discharged outside the furnace. Therefore, the charged material such as the iron raw material is gradually lowered with the progress of the reduction reaction and the melting, and a new charged material is charged from the top of the furnace accordingly. The falling condition of the furnace interior charge and the new charging condition affect the layer thickness distribution of the charge, but there is a certain relationship between the layer thickness distribution and the blast furnace operating condition, and the gas inside the furnace It also affects the flow distribution and the shape of the cohesive zone. Therefore, knowing the layer thickness distribution of the charge is a factor that determines the condition of the gas flow in the furnace and the shape of the cohesive zone, and in turn the factor that determines the reduction efficiency. This is also important for proper control of the charging / falling position in the direction, and this makes it possible to achieve stable blast furnace operation with high reduction efficiency.

Conventionally, the layer thickness distribution adjustment control of this charge is performed by adjusting the position of the armor plate as the layer thickness distribution means of the bell-type blast furnace and adjusting the turning angle of the turning chute of the bellless-type blast furnace. However, for example, the relationship between the adjustment operation of the armor plate of the bell-type blast furnace and the layer thickness distribution state of the charge is only known by model experiments, and the layer thickness distribution state in the actual blast furnace operation is Different from Therefore, accurate understanding of the layer thickness distribution of the charge during the actual operation was necessary in order to improve the accuracy of the charge control. Therefore, as a method for detecting the layer thickness distribution state of this charge, for example, Japanese Patent Application Laid-Open No. 58-22.
As described in Japanese Patent No. 313, an infrared television camera provided at the top of a blast furnace measures a temperature distribution pattern of the surface temperature of a charge deposited in the furnace, and measures the measured pattern at a high temperature. There is known a method of detecting a change in the area ratio of the high and low areas by dividing the area into a low temperature area and a low temperature area.

[0004]

However, even if the temperature distribution pattern of the charge is measured by using the infrared television camera and the charge distribution is adjusted based on the temperature distribution pattern as described above, the temperature distribution pattern from the top side of the furnace is the limit. Since it is the distribution adjustment of the charge based on the obtained data, it cannot be said that the adjustment is compatible with the situation of the gas flow and the shape of the cohesive zone that change depending on the situation inside the furnace at that time, and the reduction rate is Due to fluctuations, it was not enough to maintain the stability of blast furnace operation.

The present invention has been made in view of the above circumstances. By adjusting the dropping position of the ore of the charge according to the situation in the furnace, the reduction efficiency can be improved and the operation of the blast furnace can be stabilized. An object of the present invention is to provide a blast furnace control method and apparatus.

[0006]

A method according to the above-mentioned object.
The control method of the blast furnace described is to determine the furnace gas temperature on the furnace center side and the furnace wall side from the furnace core surface at the blast furnace furnace belly position, and when the temperature is the furnace center side ≦ furnace wall side, the furnace top Adjust the relative O / C in the furnace radial direction of the charge charged from
The temperature on the furnace center side is higher than the temperature on the furnace wall side. The relative O / C as used herein is the ratio of the local O / C measured by a measuring means such as a sounding device to the O / C of all the charges.

The control method of the blast furnace according to claim 2 is
The line that connects the center of the blast furnace and the tip of the tuyere between the lower part of the shaft and the upper part of the furnace belly on the center line of the blast furnace is defined as the furnace core surface position, and the tip is inserted into and out of the furnace from outside the line. If possible temperature measuring means is provided, the temperature of the gas in the furnace on the furnace center side and the furnace wall side from the straight line is obtained by the temperature measuring means, and when the temperature is in the furnace center side ≦ furnace wall side, the furnace top Relative O / in the furnace radial direction of the charge charged from
By adjusting C, the average temperature is set so that the furnace center side> the furnace wall side. The position of the surface of the furnace core may be estimated in this way, but the insertion thrust force may be measured when inserting the temperature measuring means to be inserted into the furnace, and estimated from the measured thrust value. The relative O / C near the furnace wall can be adjusted by adjusting the armor plate in the bell-type blast furnace and adjusting the turning angle of the turning chute in the bellless blast furnace.

Further, according to a third aspect of the present invention, there is provided a control device for a blast furnace, comprising: temperature measuring means for measuring the temperature of the gas inside the furnace on the side of the furnace center and the wall of the furnace, and the temperature of the gas inside the furnace measured by the temperature measuring means. When the average temperature on the furnace center side and the average temperature on the furnace wall side are obtained and it is determined that these average temperatures are within the furnace center side ≦ the furnace wall side, the relative O near the furnace wall is determined.
/ C to reduce the average temperature on the furnace center side> the average temperature on the furnace wall side so that an operation command signal is sent to the adjustment drive means of the layer thickness distribution adjusting means in the furnace radial direction of the charge material charged from the furnace top. And a control means for outputting

[0009]

The present inventors investigated and examined the relationship between the shape of the cohesive zone, the air permeability of the core, and the gas inside the core. As a result, the surface of the core was first found to be on the center line of the blast furnace as shown in FIG. It was found that it is represented by a straight line connecting the blast furnace central portion X, which is an arbitrary point a between the lower portion of the shaft to the upper portion of the furnace belly, and the tuyere tip Y. A point B is an intersection of a line AC connecting a point A on the furnace center side with a point C on the furnace wall side of the straight line XY and a straight line XY. The height position of the blast furnace central portion X between the lower part of the shaft and the upper part of the furnace abdomen on the center line of the blast furnace is determined according to the fact that the core surface position of each blast furnace is slightly different. In addition, for example, a temperature detecting unit, which is an example of temperature measuring means inserted from the furnace wall, is inserted to
When the average temperature Tab at a plurality of points between B and the average temperature Tbc at a plurality of points between BC are actually measured, when stable operation is performed, Tab> Tbc, and unstable operation is performed. In this case, it was found that Tab <Tbc. That is, the gas permeability of the furnace core is good, a large amount of gas in the furnace passes, the shape of the cohesive zone becomes an inverted V shape, and the gas flow in the furnace becomes a peripheral flow. On the other hand, is because the air permeability of the furnace core is poor and the gas flow rate inside the furnace is small,
The shape of the cohesive zone is an inverted U shape, and the gas flow in the furnace is the central flow.

From the graph of FIG. 3 showing the relationship between the average temperature between BC and the average temperature between AB (hereinafter referred to as BC-AB temperature) and the relative O / C near the furnace wall at the top of the furnace, It can be seen that the relationship between
If increases or decreases, the BC-AB temperature also increases or decreases. Therefore, the temperatures on the furnace center side (furnace center side from the XY line) and the furnace wall side (furnace wall side from the XY line) are measured, and the relationship between the mean temperature on the furnace center side and the mean temperature on the furnace wall side is When the center side ≦ furnace wall side, for example, O of the total amount of the charging material charged from the furnace top
By adjusting the armor plate under the condition that / C is constant, the O / C in the vicinity of the furnace wall is reduced, that is, the amount of ore charged to the center side of the furnace is increased, whereby BC-AB
The temperature is lowered to adjust the charge distribution so that the temperature of the furnace center side> the temperature of the furnace wall side. That is, by charging a large amount of ore into the center of the furnace to suppress the central flow of the gas flow in the furnace, the fusion zone is formed into an inverted V shape to increase the amount of gas in the furnace flowing through the core, and BC -Adjust the AB temperature. As a result,
As shown in FIG. 4, the ventilation resistance is reduced, the reduction efficiency is improved, the amount of tapping metal is increased, and the operation stability of the blast furnace is improved.

[0011]

EXAMPLES Next, examples embodying the present invention will be described to provide an understanding of the present invention, but it goes without saying that the present invention is not limited to these examples.

Examples 1 to 3 The bell-type blast furnace 10 having an internal volume of 5245 m ³ and a length of 6 m from the tuyere tip to the furnace center line was used. As shown in FIG. 1, the tuyere 11 was placed on the center line of the blast furnace. The center position X of the blast furnace is located at a height of 7 m from the center position X and the tuyere tip Y is connected by a straight line. From the height of 5m from the tuyere 11 diagonally downward 25
The temperature detecting unit 12 of the temperature measuring means is inserted at an angle of degrees, and the tip (detecting end) of the inserted temperature detecting unit 12 intersects the point A and the straight line XY at a position 1 m to the furnace center side from the straight line XY. Point B, the position returned to the furnace wall side by 1 m is point C,
At this time, the furnace temperature is measured at five points A, B, C and the center between the points. A detection signal from the temperature detection unit 12 is sent to the control unit 13, and the control unit 13 adjusts and drives the armor plate 14 of, for example, a bell type blast furnace arranged above the furnace top of the blast furnace 10 based on the detection signal. By this, an operation command is issued to increase the ratio of ore charged to the center of the furnace and reduce the relative O / C in the vicinity of the furnace wall.
As a result, the armor plate 14 moves to the inside of the furnace, and the relative O / C in the vicinity of the furnace wall is adjusted so that the average temperatures on the furnace center side and the furnace wall side are greater than the furnace center side> the furnace wall side.

Under the operating conditions shown in Table 1 before each adjustment, the straight line X
The furnace gas was measured at each of the measurement points on the furnace center side AB and the furnace wall side BC from Y, and the respective average temperatures were obtained.

[0014]

[Table 1]

As is clear from Table 1, in the blast furnace operating methods of Examples 1 to 3, the average temperatures of the in-furnace gas on the furnace center side and the furnace wall side were determined from the straight line XY in FIG.
At the top of the furnace, to maintain the furnace center side> furnace wall side,
Since the adjustment was made to lower the relative O / C in the vicinity of the furnace wall by 0.7 to 0.8, the fuel ratio was 3 to 10% compared to that before the adjustment.
6Kg / T-pig reduced, tapping amount improved by 50-200T / D, ventilation resistance index decreased by 0.04-0.08, solution loss carbon reduced by 1-2Kg / T-pig,
Silicon in hot metal decreased by 0.03 to 0.04%. As is apparent from these results, according to the present invention, the relative O / C in the vicinity of the furnace wall is determined according to the situation in the furnace such that the average temperature of the furnace gas on the furnace center side and the furnace wall side with respect to the straight line XY is the furnace center side> The reduction efficiency and the quality of the hot metal are improved by adjusting so that it will be on the furnace wall side. Moreover, stable blast furnace operation can be realized by maintaining the state in which the average temperature of the gas in the furnace is on the side of the center of the furnace> the side of the furnace wall.

[0016]

As described above, the blast furnace center portion between the shaft lower portion and the furnace belly portion upper portion on the center line of the blast furnace and the tuyere tip are connected by a straight line, and on the furnace center side and the furnace wall side of the straight line, respectively. The average temperature of the gas in the furnace at a plurality of points was determined, and the relative O / C of the furnace top was adjusted so that the average temperature was kept higher than the furnace center side> the furnace wall side. It is possible to improve the reduction efficiency of the produced ore and stabilize the blast furnace condition.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a blast furnace to which a method for controlling a blast furnace according to an embodiment of the present invention is applied.

FIG. 2 is a schematic sectional view of a blast furnace to which a blast furnace control method according to an embodiment of the present invention is applied.

FIG. 3 is a graph showing the relationship between the average temperature between BC and the average temperature between AB and the relative O / C in the vicinity of the furnace wall.

FIG. 4 is a graph showing a relationship between an average temperature between BC and an average temperature between AB and a ventilation resistance index.

[Explanation of symbols]

 10 Blast Furnace 11 Tuyere 12 Detection End 13 Control Means 14 Armor Plate 15 Adjustment Driving Means

Claims (3)

[Claims] 1. A furnace gas temperature on the furnace center side and the furnace wall side from the furnace core surface at the blast furnace furnace abdomen position is determined, and when the temperature is within the furnace center side ≦ furnace wall side, charging is performed from the furnace top. A method for controlling a blast furnace, characterized in that the relative O / C in the furnace radial direction of the charged material is adjusted so that the furnace center side temperature> furnace wall side temperature. 2. A furnace core surface position is located on the line connecting the center of the blast furnace and the tip of the tuyere between the lower part of the shaft and the upper part of the furnace belly on the center line of the blast furnace, and the tip from outside the furnace is more than the straight line. A temperature measuring means that can be inserted into and removed from the inside of the furnace is provided, and the temperature of the gas in the furnace on the furnace center side and the furnace wall side from the straight line is obtained by the temperature measuring means, and the temperature becomes the furnace center side ≦ furnace wall side. At this time, the blast furnace control method is characterized in that the relative O / C in the furnace radial direction of the charging material charged from the furnace top is adjusted so that the average temperature is set to the furnace center side> furnace wall side. 3. A temperature measuring means for measuring the temperature of the in-furnace gas on the furnace center side and the furnace wall side of the blast furnace, and an average temperature on the furnace center side and the furnace wall from the furnace gas temperature measured by the temperature measuring means. Side average temperature, and when it is determined that these average temperatures are within the furnace center side ≦ furnace wall side, the relative O / C in the vicinity of the furnace wall is reduced, and the furnace center side average temperature> And a control means for outputting an operation command signal to the adjustment drive means of the layer thickness distribution adjustment means in the furnace radial direction of the charge charged from the furnace top so that the average temperature on the furnace wall side is reached. Blast furnace controller.